Internal Parasite Or Bacterial Infection?

[doubledee]

I added some corydoras similis and pencilfish to my newly cycled tank about ten days ago or so. All the stats were fine and the tank is medium planted. I did a 90% waterchange on the morning prior to getting fish after all parameters indicated that tank was cycled. One of the corydoras died within hours of going in the tank, which I put down to the stress of the journey (three hours but bag was oxygenated).

However, about seven days later one of the pencil fish was swimming on it's side and eventually died. Again all the water stats were fine. The pencil fish do seem to be agressive sometimes and wondered if it was a male that had succumb to the agressions of one of the others. They have been fine otherwise and I'm confident they will breed as they have been displaying spawning like behaviour (within hours of going in the tank).

Two days ago, I noticed one of the corydoras resting on a plant leaf near the surface of the water. I later spotted him swimming to the surface (as they do) but sinking to the bottom of the tank. He then just laid on his side, again, occasionally swimming to the surface and returning to the substrate.

All the other fish are feeding fine but I have noticed a couple of the corydoras darting around and 'flicking'. There are no visible signs of any parasite and their gills are not red.

Could it be something similar to the problem reported in this thread http/www.fishforums.net/Corydora-With-Re...ll-t193843.html

Can anyone suggest a remedy should I experience any further problems?

Tank size: 180litres
pH: 7.0
ammonia: 0
nitrite: 0
nitrate: <10
kH: not tested
gH: not tested
tank temp: 26

Fish Symptoms (include full description including lesion, color, location, fish behavior): See above re. occasional flicking

Volume and Frequency of water changes: Only 25 percent changed thus far (tank is about 10 days matured after cycling)

Chemical Additives or Media in your tank: API plant zone

Tank inhabitants: 6 Corydoras similis, 5 diptail pencilfish, snails (unfortunately)

Recent additions to your tank (living or decoration): None

Exposure to chemicals: None

 

[Spooky76]

Hey - sounds a bit tricky. Might be worth checking your co2 levels. Which you can do by using your PH and Kh (In degrees). Have you got air stones or a massive power head running ? Is your temp OK ?

Other than that I havent got a clue sorry I cant help. I dont have many catfish, my little one just seems to carry on no matter what happens. Hopefully someone with experience of these fish will help you.

 

[doubledee]

I'm not injecting any co2 as I didn't want any hassles from it! I like planted tanks but have stuck with easy to grow plants and standard lighting. It's working just fine and the plants are growing. The temp (26deg C) is ok for both species. The only aeration at the moment is from the return on the external filter. The flow is quite strong and the corys' seem to enjoy playing in it!

 

[WILDER]

What was the ph of the lfs to your tank, how long did you climatise them for.

 

[doubledee]

What was the ph of the lfs to your tank, how long did you climatise them for.

I'm not sure what the ph of the LFS tank water was. I didn't think to check as I took a long time to acclimitise them. The bag was floated for about 20 mins then I added a half cup of water every 5 mins or so filling the bag then reducing it by half and repeating the half cup every 5 min routine. I spent over an hour on acclimitising them.

 

[WILDER]

It sounds like ph shock to me.
pH Shock

As its name suggests this condition occurs when a fish is introduced to quickly into a new environment which has a very different pH from the one it came from, when the pH is adjusted to quickly and the fish have little or no time to adjust themselves, or when the pH is to far outside the fishes normal range.

It is very important that any change in water chemistry is made slowly and fish should never be exposed to changes of pH greater than 0.5 of one unit on the pH scale in either direction.

Avoidance is by far the best solution because in most cases the symptoms don't appear until the second or third day by which time the damage has been done and the fish will probably die.

A fish suffering from this condition will show all the typical signs of shock -

Lying on the bottom and paying little or no attention to its surroundings and ignoring potential threats.
It may even lay on its side or go upside down completely.
There could be other signs to, related to Acidosis and Alkalosis
Excessive mucus production.
Rapid breathing.
Swollen abdomen. (Alkalosis only).
If the condition is allowed to go on for one or two days then the chances of a successful remedy are greatly reduced because a lot of damage will have taken place. If the symptoms are spotted early enough there are a couple of things that will help.

Begin to return the pH to the original pH in steps of 0.4 of one unit on the pH scale and allow 3 hrs in between the adjustments. Make these adjustments until the pH is returned to a safe and satisfactory level.
Treat the tank with a broad spectrum anti-Bacteria/Fungus compound to prevent secondary infections of the Skin and Gills.
Prevention is easy. A successful treatment isn't!